The present invention relates generally to improvements in loudspeaker assemblies, and specifically to the provision of a loudspeaker assembly incorporating a first speaker for reproducing audio mid frequencies and audio high frequencies and a second speaker for reproducing audio low frequencies, the speakers being arranged so as to provide controlled dispersion of the mid frequencies and high frequencies and low frequency saturation.
The speaker assembly of the present invention is particularly adapted for use in vehicles and other confined spaces. A typical place for mounting the speaker assembly of the present invention is on the package deck of an automobile just in front of the rear window, or in side panels and door panels in such vehicles. Problems have been encountered in providing adequate sound reproduction in such vehicles heretofore because in an attempt to overcome road noises, mechanical noises and wind noises, which are dominantly in the low frequency range, such vehicles are designed with the most sound absorbent interiors possible. As a result, it is necessary to utilize a very large speaker for reproducing the audio low frequencies to overcome the above noted noises and sound absorbent interiors in order to produce the necessary bass saturation. The provision of the large low frequency speaker presents a space utilization problem. The mid frequency and high frequency speaker also presents a problem in obtaining optimum dispersion of these frequencies.
Prior to the present invention, vehicle speakers fell into two broad classifications: (1) a surface mounted small wedge or box and (2) a flush-mounted door, deck or panel type. The small wedge or box is limited in allowable speaker size to reproduce the low frequencies by visibility and available space considerations on the package shelf. Limiting the size of the low frequency speaker in turn limits the bass response which is directly related thereto. The flush mounted speaker, which might be a co/tri axial or 2+2 (woofer and tweeter), cannot control the dispersion of high frequencies and mid frequencies. If the flush mount is on the rear package deck, the mid frequencies and high frequencies are lost when the sound hits the overlying rear window. In some cases the angle of inclination of the rear window reflects the sound into the liner covering the roof of the vehicle or below the ear level of the listener. If the flush mount is in the door or side panel, mid frequencies and high frequencies are normally driven into the feet, seats or across a narrow path, usually out of the listeners range. If the flush mount system is a co/tri axial, the low frequencies are sacrificed and too many mid frequencies are produced.
These various problems are solved in the present invention by providing two speakers, one being a woofer to reproduce the audio low frequencies, the other being an exponential horn to reproduce the audio mid frequencies and the audio high frequencies, the acoustical axes of the speakers being arranged essentially normal with the acoustical axis of the speaker reproducing the mid frequencies and the high frequencies being directed essentially toward the ears of the listener. Such an arrangement provides for controlled dispersion of the mid and high frequencies which are very directional with the beam or path of the sound being narrower as the frequency increases. By directing the dispersion of the mid frequencies and high frequencies at the ears of the listener, every passenger within the vehicle receives the same frequency balance, with the mid frequencies and the high frequencies smooth, clean and clear. The novel arrangement of the present invention also provides low frequency saturation from the speaker reproducing the low frequencies. The low frequency speaker being free of restricting plates, brackets, and the like, has no corresponding wave stand off and phase cancellation. As a result, there is an efficient generation of the low frequencies and full distribution thereof and saturation within the passenger compartment of the vehicle.
U.S. Pat. No. 2,688,373 granted Sept. 7, 1954 to H. F. Olson shows two speakers with the axes disposed normal to each other, but the speakers are not arranged in the housing in accordance with the present invention, and rather the audio high frequencies must in some fashion pass through the cone of the low frequency speaker, which arrangement has been found to be unsatisfactory. U.S. Pat. No. 2,927,657 granted Mar. 8, 1960 to L. J. Patla et al. also shows speakers with the acoustical axes thereof disposed normal to each other, but the speakers are disposed in separate housings so as not to achieve the very substantial economy of space required for the successful mounting in vehicles such as in the present invention. U.S. Pat. No. 3,637,938 granted Jan. 25, 1972 to H. F. Kuhlow et al. likewise shows speakers with the acoustical axes normal to each other, but the speakers are mounted in an entirely different manner than that of the present invention with respect to the housing therefor, whereas to occupy an inordinate amount of space, thus not achieving the space utilization efficiency, optimum dispersion of the mid frequencies and high frequencies, and the saturation of the low frequencies achieved by the present invention.